Potentiometer



Patented Sept. 1, 1953 UNITED STATES i ATENT OFFICE PiOTENTIOMETER Application October 4, 1951, Serial No. 249,701

2 Claims. (Cl. v2( )161) This invention relates in general to a potentiometer and in particular to apparatus for obtaining a plurality of voltages that may be independently adjusted.

It oftentimes becomes desirable in electronic equipment to obtain a number of different voltages. For example, different voltages might be proportional to shaft positions and a servo system when supplied one of the voltages will adjust the shaft to the correct position.

It is an object of this invention therefore, to provide a potentiometer wherein a number of take-01f contacts may be independently adjusted.

Another object of this invention is to provide a compact and easy to manufacture multiple tap potentiometer.

A feature of this invention is found in the pro-vision for a base plate which has a plurality of resistive wire strips mounted there, and a plurality of rotatably mounted contacts which engage the resistive wires.

Further features, objects and advantages of this invention will become apparent from the following description and claims when read in view of the drawings, in which:

Figure 1 is a top view of the multiple potentiometer of this invention;

Figure 2 is a sectional view taken on line 2-2 of Figure l; and,

Figure 3 is a rear View of the potentiometer of this invention.

Referring to Figure 1, a base plate, designated generally as I 0, is made of insulating material, as for example, Bakelite. A number of resistive wires I! are mounted on the base plate 10 between holding contacts l2. The resistance wire I I might be made of nichrome, for example, and the resistance of each of the wires might vary as, for example, 180 ohms per inch for the first wire, 240 ohms for the second wire, and 385 ohms for the third wire.

A high voltage is connected between the contact [2 attached to one end of the first resistive wire H and one of the contacts 12 attached to the end of the last resistive wire. As shown in the rear view, Figure 3, jumpers I3 and I4 connect one end of the first row with one end of the second row. The other end of the second row is connected by a jumper 14 to one end of the last row. Thus, a voltage is impressed between the first end of the first row and the last end of the second row and causes current to flow through the three resistive wires.

A number of rotary contacts 16 are mounted to the base plate I0 as best shown in the sectional view (Figure 2). A pin I! passes through an opening formed in the base plate It and is connected to a connection bar I3 which is fastened to the base plate by a second pin l9. An insulated head 2i, as for example, Bakelite, is rigidly attached to one end of the pin I! and is formed with a slot 22 which may be used for rotating it with a screw driver.

A rotary arm 2!] is connected to the pin I I and its outer end 23 engages the resistive wire H.

An output lead may be connected to the bar 58. The length of the arm 20 is such that it may rotate somewhat to vary the voltage picked 3 up to thus allow minute adjustments to be made.

A protective plate 24 which might be made of plastic, for example, is attached to the base plate [0 by stand-oifs 26 which threadedly receive bolts 2'! and form a safety shield over the wires and contacts. As shown in Figure 1, openings are formed in the safety shield 24 over the insulated heads 22 so that a screw driver may be inserted to adjust them. The contacts, however, are not readily accessible and thus do not offer a hazard.

In operation, the voltage supply is connected between the first and last resistive wires and a screw driver is used to set the contacts [6 to the desired voltages. Since each contact may be adjusted, the positions of the pins I1 is not critical and large tolerances may be used in punching the openings through the base.

In the event that it is desired to change the voltage increments, the contacts may be moved to a new position.

It is seen that this invention provides a multiple tap potentiometer wherein the voltage of each tapped point may be independently adjusted as desired.

Although this invention has been described with respect to a particular embodiment thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope of the invention as defined by the appended claims.

I claim:

1. A multiple tap potentiometer comprising, an insulated base plate, a plurality of conductive wires mounted on said base plate, a plurality of jumpers connecting the ends of the conductive wires to other conductive wires, a plurality of rotary adjustable contacts mounted to said base member adjacent said resistive wires and formed with rotary arms for engaging said resistive wires, and a protective plate mounted over said resistive wires and formed with opena ings therein so that the rotary contacts may be adjusted.

2. A multiple tap potentiometer comprising, an insulated base plate, a plurality of straight resistive Wires mounted on said base plate, a plurality of jumpers connecting the ends of said Wires, a plurality of rotary adjustable arms mounted in said base plate and in slide contact with said resistive Wires, a conducting shaft fixed to each rotary arm and extending through said base plate, a plurality of connecting bars attached to the back of said base plate and slidably connected to the shafts of said rotary arms,

NORMAN S. HIME.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Merle Dec. 2, 1930 Number 

